[PATCH 5/7] crypto: hisilicon/hpre - fix GFP flags for dma_alloc_coherent

[Weili Qian]

The HPRE driver hard-codes GFP_ATOMIC for RSA/DH and GFP_KERNEL for
ECDH. This may cause "scheduling while atomic" in atomic context or
unnecessary allocation failures under memory pressure.

Select GFP flags dynamically based on CRYPTO_TFM_REQ_MAY_SLEEP and
store them in hpre_asym_request::flags. The areq field is a union of
rsa/dh/ecdh request pointers; reading base.flags through any union
member other than the one that was written would be type-punning, so
a dedicated flags field avoids that.

Fixes: 98dfa9343f37 ("crypto: hisilicon/hpre - don't use GFP_KERNEL to alloc mem during softirq")
Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: Weili Qian <qianweili@xxxxxxxxxx>
---
 drivers/crypto/hisilicon/hpre/hpre_crypto.c | 10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)

diff --git a/drivers/crypto/hisilicon/hpre/hpre_crypto.c b/drivers/crypto/hisilicon/hpre/hpre_crypto.c
index f77c318caa35..6ca34f3bf9ff 100644
--- a/drivers/crypto/hisilicon/hpre/hpre_crypto.c
+++ b/drivers/crypto/hisilicon/hpre/hpre_crypto.c
@@ -138,6 +138,7 @@ struct hpre_asym_request {
 	int err;
 	hpre_cb cb;
 	struct timespec64 req_time;
+	u32 flags;
 };
 
 static inline unsigned int hpre_align_sz(void)
@@ -186,6 +187,7 @@ static int hpre_prepare_dma_buf(struct hpre_asym_request *hpre_req,
 				struct scatterlist *data, unsigned int len,
 				int is_src, dma_addr_t *tmp)
 {
+	gfp_t gfp = hpre_req->flags & CRYPTO_TFM_REQ_MAY_SLEEP ? GFP_KERNEL : GFP_ATOMIC;
 	struct hpre_ctx *ctx = hpre_req->ctx;
 	struct device *dev = ctx->dev;
 	void *ptr;
@@ -195,7 +197,7 @@ static int hpre_prepare_dma_buf(struct hpre_asym_request *hpre_req,
 	if (unlikely(shift < 0))
 		return -EINVAL;
 
-	ptr = dma_alloc_coherent(dev, ctx->key_sz, tmp, GFP_ATOMIC);
+	ptr = dma_alloc_coherent(dev, ctx->key_sz, tmp, gfp);
 	if (unlikely(!ptr))
 		return -ENOMEM;
 
@@ -419,6 +421,7 @@ static int hpre_msg_request_set(struct hpre_ctx *ctx, void *req, bool is_rsa)
 		h_req = PTR_ALIGN(tmp, hpre_align_sz());
 		h_req->cb = hpre_rsa_cb;
 		h_req->areq.rsa = akreq;
+		h_req->flags = akreq->base.flags;
 		msg = &h_req->req;
 		memset(msg, 0, sizeof(*msg));
 	} else {
@@ -433,6 +436,7 @@ static int hpre_msg_request_set(struct hpre_ctx *ctx, void *req, bool is_rsa)
 		h_req = PTR_ALIGN(tmp, hpre_align_sz());
 		h_req->cb = hpre_dh_cb;
 		h_req->areq.dh = kreq;
+		h_req->flags = kreq->base.flags;
 		msg = &h_req->req;
 		memset(msg, 0, sizeof(*msg));
 		msg->key = cpu_to_le64(ctx->dh.dma_xa_p);
@@ -1457,6 +1461,7 @@ static int hpre_ecdh_msg_request_set(struct hpre_ctx *ctx,
 	h_req = PTR_ALIGN(tmp, hpre_align_sz());
 	h_req->cb = hpre_ecdh_cb;
 	h_req->areq.ecdh = req;
+	h_req->flags = req->base.flags;
 	msg = &h_req->req;
 	memset(msg, 0, sizeof(*msg));
 	msg->in = cpu_to_le64(DMA_MAPPING_ERROR);
@@ -1475,6 +1480,7 @@ static int hpre_ecdh_msg_request_set(struct hpre_ctx *ctx,
 static int hpre_ecdh_src_data_init(struct hpre_asym_request *hpre_req,
 				   struct scatterlist *data, unsigned int len)
 {
+	gfp_t gfp = hpre_req->flags & CRYPTO_TFM_REQ_MAY_SLEEP ? GFP_KERNEL : GFP_ATOMIC;
 	struct hpre_sqe *msg = &hpre_req->req;
 	struct hpre_ctx *ctx = hpre_req->ctx;
 	struct device *dev = ctx->dev;
@@ -1488,7 +1494,7 @@ static int hpre_ecdh_src_data_init(struct hpre_asym_request *hpre_req,
 	if (unlikely(shift < 0))
 		return -EINVAL;
 
-	ptr = dma_alloc_coherent(dev, ctx->key_sz << 2, &dma, GFP_KERNEL);
+	ptr = dma_alloc_coherent(dev, ctx->key_sz << 2, &dma, gfp);
 	if (unlikely(!ptr))
 		return -ENOMEM;
 
-- 
2.43.0